depth in partially full pipe equation in excel

[atxeng]

I see on past discussions taht there is a spreadsheet floating around with an iterative equation for depth of flow in a partially full pipe. Here in Austin we are required to design to 85% full or less for the 100 year. Being from Houston, we always assumed full flow and designed for 2 year storms. can anyone send me a spreadsheet so that I don't have to consult a hydrograph or land desktop.

 

[LHA]

Here are the equations, solved for a 36" pipe. Copy all into cell A1 of a new .xls, then pretty it up.

Circular Section Conveyance
Ratio Full Flow d/D
0.00 0.00
0.10 0.15
0.25 0.30
0.35 0.38
0.50 0.50
0.65 0.62
0.75 0.70
0.85 0.78
1.00 1.00

D = Diameter 36
Ratio Full Flow desired = 0.85
d/D = 0.78 '=VLOOKUP(B14,A3:B11,2)
d = Flow Depth, ft 0.228 =B13*B15/123

A = 0.25D * WP + d - 0.5D * [d(D-d)]^0.5 = Area, sq ft = 0.88 =0.25*(B13/12)*B20+B16-0.5*(B13/12)*(B16*((B13/12)-B16))^0.5

WP = 0.5piD + D * Sin[(2d -D) /D] = Wetted Perimeter, ft = 2.46 =0.5*PI()*(B13/12)+(B13/12)*SIN((2*B16-(B13/12))/(B13/12))

T = 2 * [d(D-d)]^0.5 = Top Width, ft = 1.59 =2*(B16*((B13/12)-B16))^0.5


Engineering is the practice of the art of science - Steve

 

[atxeng]

I think a 3 snuck into your depth of flow calculation. How about converting flows and slopes to depths of flows.